9,999,999/Historical Note

Historical Note on $9 \, 999 \, 999$

When John Napier invented what are now known as Napierian logarithms, he assigned the number $10 \, 000 \, 000$ the logarithm $0$, and the number $9 \, 999 \, 999$ the logarithm $1$.

Then, by repeatedly multiplying by $\dfrac {9 \, 999 \, 999} {10 \, 000 \, 000}$, he built the sequence of numbers that had the logarithm $2, 3, 4, \ldots$

Sources

• 1986: David Wells: Curious and Interesting Numbers ... (previous) ... (next): $9,999,999$
• 1997: David Wells: Curious and Interesting Numbers (2nd ed.) ... (previous) ... (next): $9,999,999$